1. Field of the Invention
This invention relates to the field of reading machines, and more particularly to a fully portable scanner that enables users to easily scan a block or column of text and hear the text recited audibly.
2. Description of the Prior Art
In recent years, the advance of electronics and computer technology has enabled the development of a number of devices that assist with ordinary tasks that entail reading and assimilating information in printed form.
Much of the development activity has centered on bar code scanning technology. Bar coding is a process for encoding information in a printed, graphic form. Typically a bar code is provided as a pattern printed in a specially appointed area on a paper or on packaging containing an item of manufacture or commerce. The pattern comprises a series of parallel printed lines of substantially equal length alternating with areas left unprinted. Various alternatives to traditional printing, including embossing, painting, screen-printing, and the like may also be used to form the pattern. The relationship of width and spacing of the printed lines, and the unprinted areas therebetween, encodes information. In the retail environment, individually packaged items offered for sale are now commonly imprinted with a standardized bar code, sometimes called a UPC code, which indicates the contents of a package. A cashier is equipped with a cash register that includes a reader adapted to optically scan the bar code for each item being purchased. Means are provided for ascertaining from a database the retail price of each item, accumulating a list of the items purchased, and providing the customer with a printed document itemizing the goods purchased and the total cost thereof. The cash register may also transmit to a remote computer an enumeration of the items sold for inventory tracking and control purposes.
Bar code systems are widely used in industry as a means of reliably tracking inventory and the flow of items in a manufacturing, warehouse, transportation, or retail environment. Items appointed for control frequently have a bar code imprinted directly thereon or carried by an auxiliary tag present either on the item itself or on its packaging. A pre-assigned bar code is used to identify a given item. Each item may be given a unique code; or items belonging to a common class may share a common code. Readers or scanners in various forms may be used to carry out inventory or article flow tasks commonly required in the course of business. Use of bar coding has a number of advantages, including improved reliability, since the possibility of human error in data entry is virtually eliminated.
The widespread use of bar code systems has been facilitated by the availability of reliable and cost-effective readers. The task of scanning bar codes is greatly simplified by the predictable and inherently simple, binary-like form in which they are presented for interrogation. In a given environment the bar code is printed according to a pre-defined format and size and is typically located in a standardized position. Thus the lines in a bar code are of predictable size and shape and appear in a fixed geometrical pattern relative to each other.
The simplicity of bar codes enables a relatively simple reader or scanner to be able to acquire an image optically and to convert it reliably into a corresponding electrical signal. Generally stated, a bar code reader comprises a light source, often a small laser source, that impinges a light beam onto an area of a surface on which the bar code is present and a photo detector or similar means of detecting the intensity of light reflected from the area into the reader. A simple linear scan traversing the bar code and sensing the variation in reflectivity along the line is sufficient to acquire all the information conveyed by the bar code. Simple forms of bar code readers rely on a user to manually scan the reader across the bar code. More sophisticated forms of reader further comprise an optical system using a moving mirror to automatically scan the light beam across an area of interest.
Scanning operations intended to acquire arbitrary textual and graphic information present a much more formidable challenge than do simple bar codes scanning operations. Printed items encountered in everyday life incorporate a very disparate variety of text fonts, sizes, spacings, and alignments. Moreover, the nuances differentiating certain letter pairs of the Roman alphabet are very slight. In addition, the simple, one-dimensional, linear scan that suffices for bar code reading is not adequate. Instead, the scan must acquire information over a two-dimensional area.
Tools have also been proposed to assist those whose ability to read is impaired by visual or perceptual difficulties. For example, tabletop scanners are available which may be connected to a personal computer (PC). A book or other printed matter may be positioned atop the scanner. The page presented may be scanned in its entirety. The resulting image is fed to the PC, where it is converted to a machine-readable text file through use of optical character recognition (OCR) software. The PC may further be interfaced with speech synthesis system to read out that text file. However, such systems have a number of limitations. They are large in size, have a fixed window of imaging area, and must be accommodated on a table or desktop. They require a source of ordinary household electrical current. Together these factors make existing systems impractical for portable use. Moreover, these systems lack simple means for the user to define a particular selection or subset of a larger text being presented. The challenge is particularly severe in dealing with printed material presented in a complex layout, such as a newspaper, in which text is organized in columns and a given story may span multiple columns having different lengths. Existing systems must rely either on further user intervention or contextual software processing after an image has already been acquired or pre-scanned to accomplish the limiting function. The multiple steps necessitated by either approach entail significant difficulties. The time required for the complete task of presenting, scanning, selecting, and processing a text increases. Highly sophisticated software is required, so a powerful and expensive computer processing facility is needed. The user must cope with a system, which lacks convenience and ease of use. While these systems have clearly benefited persons who are blind or face significant visual impairment, it would be highly desirable to have systems that are simpler to construct and use, less bulky and unwieldy so they can be made portable for a wider range of uses. Such systems would also benefit users having perceptual or learning disabilities that impair reading and comprehension of printed materials in a variety of contexts.